Electromagnetic vibrator



Jan. 20. 11925. Y

1,523,540 H. HEcHT- Filed' Nov. 1v, "1921;

narran STATES PATENT OFFICE.

HEINRICH HECHT, OF'KIEL, GERMANY, ASSIGNOR T0 SIGNAL, GESELLSCHAFT MITBESCHRANKTER HAFTUNG. OF KIEL, GERMANY.

ELECTROMAGNETIC VIBRATOR.

Application lcd November v1, 1921. Serial No. 512,077.

To all whom, t may concer/i.'

Be it known that l, llamaron llnoH'r, citizen of the -German Republic,and residing at Kiel, county oi' behleswig-llolstein, State otl Prussia,Germany, have invented certain new and useful l1iip1o.'enie1its inElectromagnetic Vibrators, olf which the following is a specification.

The invention relates in general to tele-- phones and more particularlyto telephone receivers. The object of the invention is to produce'anovel type ot' telephone receivers of a greatlyimproved eletromagneticetliciency. 'lhe improvement is, of course, applicable toall other kindsof eletromagnetic vibrators whose construction is similar to that of atelephone receiver. The invention is based on the fundamental idea that,to improve the eiiiciency of the telephone receiver, it is notsufficient lo reduce only one oil the kinds olosses, or a certain groupof the losses, that occur in this instrument, as has been done hitherto.Indistinction hererom the present inventioncontemplates the simultaneousreduction of all the various kinds ot' losses that occur in a telephoneand especially of all the electrical and magnetic losses.

The vinvention effects a reduction in (a) the iron. losses, (Zi) thevibrating masses ol' the armatt'ue and the receiver diaphragm. and (c)the copper losses.

The eiiiciency ot' a telephone receiver or any similar electromagneticvibrator' depends upon a const-ant c that is determined by the equation1 Vin which m denotes the vibrating mass (armature With its elasticsupport), B .the magnetic lines of force, 7a anotherconstant, and e thelosses occurring in. the iron. The smaller m and e become and thegreater the value of B, the greater will be the valueA of c and thegreater the electromagnetic oliiciency of the apparatus. Theabove-inelitioned improvements (a) and (b) operate in this direction.

But in accordance with the recognized fact underlying the presentinvention, the greatest possible etliciency of a telephone receiver canonly be attained it the copper losses also are reduced, and the bestcompromise Will be obtained when the iron losses are t'ormer usuallyconsist-ing of a ring-shaped or U-shaped magnet, and the path fc thelatter comprising pole pieces attached to the said magnet. lVith thisarrangement it is not possible to Aprevent a large part of thepermancnttlux from passing straight 'from one pole piece to the other sothat an iundesired by-path t'or the lines of force is provided.

In distinction therefrom the receiver ac cording to the invention hasonly a single path for the permanent (or continuous) and alternatingfluxes.

The invention is illustrated in the drawing in which- Fig. l is aperspective view of the iron path provided for the magnetic iiuxes,

Fig. 2 is a perspective view, partly in section, of a vibrating receiverdiaphragm with an inserted laminated armature, and

Fig. 3 is a vertical transverse section, partly broken awa of aconventional telephone receiver casing in which the improved form ofreceiver is mounted.

As shown in Fig. l the metallic path, which is identical for thecontinuous and alternating magnetic fluxes, consists of a U-shaped,paramagnetic, laminated body. For permanent magnets the laminae are madeof `magnetizable steel, and for receivers in.

which the continuous tield is produced by an electromagnet, the laminzeconsist of sott sheet iron. A laminated armature as shown in Fig. l ispreferably employed in conjunction with the laminated magnet. By thesemeasures the value B is increased and e is considerably reduced incomparsion with the corresponding values in known types of receivers.

A reduction of the vibrating mass m can be obtained by inserting thelaminated arma y ,ture in the receiver diaphragm (preferably in aperforation in the saine) as shoivn in Fig. 2. iii number o'lsatisiactf'iry methods of fixing' a' laminated armature in a diaphragmwin the manner illustrated have been' evolved, but these methodsdo not form'a art of this; invention. It has also been found that thearmature may be'niade very ,th-in Without giving rise to aniinpe-rmissible increase bf its magnetic reluctance. y

Ot-course there ivill have to be a compromise here between the :smallestpossible mass and the smallest possiblegmagnetie saturation'of thearmature dependent on the shape and size of the entire magnet, i. e; on

' the magnet proper together with its arma-y ture. Calculations andexperiments have shown that on the basis of the relative measurementsofthe magnet With its armature as shown in Fig. l the thickness ot anarma-l ture giving satisfactory results is approximately defined by theequation vinwhich k denotes the height of the laminae of the armatureand 'e the thickness of the shanks ot' the magnet.

The desired reduction of the copper losses has been accomplished bygiving the magnet a certain shape and size. It will be obvious thatas aresultotq the dimensions ot the iron and of the proportions describedabove,

a definite quantity of copper will be required to diminish the copperlosses just as much as the iron losses. If the correct size of magnetvis chosen certain inostfavorable shapes exist in which the magnet maybe made. It has been ascertained by experiment that the approximatelymost favorable shape otthe magnet is Vthefliorm of a cube each edge ofWhich is equal to 1. 'Tlie'thickness i of the shank ot the vmagnetshould be If, with the magnet oit this shape, thel interior spacebetween the slianks is filled with copper windings, the aboverequirement as to the equality of theiron and copper losses will besufcient'ly satisfied. It has been found that tlieinost favorable sizefor the said cube is obtained jivheii the lengthA of each ot its edgesvl is made eqnall to 1 2 cms'. n o In 3, l denotes the. telephone case, 2the diaphragm having the laminated arma ture 3 mounted in itsfcenter. At4 is shown the` laminatedl U--shaped magnet, on the` shanks of which'the copper coils 5, 5 are placed, these coils being of such size thatthe entire space between the slianks is fillednivith" windings. i

By the collateral aplication of the `above-V described measures theentire electromagnetic efficiency `(including reduction of copperdamping', much too small for other electromagnetic vibrators such,astallz ing current amplifiers which consist of a vibratingelectromagiiet associated with a co-operatiiig' microphone or the like.Itis possible tor instance to construct a talking Acurrent amplifyingrelay or` repeater in accordance with v.the .invention Whiclnivith alsufficiently large damping (danipingz02 or more), still gives a goodamplifying e'tl'ect. Thisis rendered possible because of the highVefticiencyvolx the electromagnetic partV (greater than obtained by theinvention as distinguished fronrtlie known types of'repeaters'consisting of a telephone receiver anda microphone which haseither an unsatisfactory amplifying ei'ector` a practical use intelephony.

` I claim l.` An electromagnetic vibrator compri ing a laminatedU-shaped continuous tield magnet and a vibratory armature cooperat-ving` therewith, a winding on said magnet adapted to carry thealternating` current produced by the Vibrations of said armature, thecontinuons magnetic iluX andthe alternating umptionr 7() ent inventionis oi course important for ilux, induced during the vibrations of thearmature havingboth the saine A`path, said Winding filling the spacebetween the shank oi the U, mensioned to receive a suflicient amount ol-finding to render the losses ofenergy inthe windings equal to themagnetic energy losses.

2. An electromagnetic vibrator comprising a laminated -U-shapedlcontinuous field magnet and a vibrating diaphragm having' said fie-ldmagnet being' suitably dian armature mounted on itcooperating with saidmagnet, a winding, onsaid' magnet adapted to carry the alternatingvcurrent produced by the vibrations of said armature,

the continuousmagnetic flux and the alter- .nating flux, induced durinthe vibrations of the armature, having'bot the'same path, said windingiilling' the space between the shanks of the U, said field magnet beingsuitably diinensioiiedto'receive a' sufticient amount ot winding torender the losses of energy inthe windings equal to the magneticenergylosses.

3. An electromagnetic` vibrator compris# inga laminated Usliapedcontinuous field niagnetand a vibrating diaphragm having an armaturelmounted on it cooperating with said magnet, ,a winding on said magnet'adapted to carry the alternating current` produced by the vibrations ofsaid armature, thecontinuous magnetic linx andthe alternating flux,induced during the vvibrations of the armature, having boththe samepath,

lthereof and cooperating with said winding filling the space between'the Shanks of the U, said field magnet being suitably dimensioned toreceive a sufficient amount of winding to render the losses of energy inthe windings equal to the magnetitI energy losses, the thickness of saidarmature being suitably chosen te retain the armature below the magneticsaturation point for a given finx in the field magnet. Anelectromagnetic vibrator comprising a laminated U-shaped continuonsfield magnet and a laminated vibrating armature cooperating therewith,awinding on said magnet adapted to carry the alternating current producedby the vibrations of said armature, the continuous magnetic flux andthe. alternating fiuX, induced during the vibrationsioic the armature,having both the same path, said winding filling the space between theshanks of theU, said field magnet' being suitably dimensioned to receivea sufficient amount of winding to render the losses of energy in thewindings equal to the magnetic energy losses.

5. An electromagnetic vibrator comprising a laminatedE U-shapedcontinuous field magnet'and a vibrating diaphragm having an armatureconstituting the central portion said'- magnet, a winding on saidlmagnet adapted to carry the alternating current produced by thevibrations ot said armature, the continuons magnetic flux and thealternating flux, in-

' duced during the vibrations of the armature,

having both the same path, said Winding lling the space between theshanks of the U, said field magnet being suitably dimensioned to receivea sufficient amount of wind- -ing to render the losses of energy in thewindings equal to the magnetic energy losses.

6. An electromagnetic vibrator comprising a laminated U-shapedcontinuous field magnet and a vibrating diaphragm having an armatureconstituting the central portion thereof and cooperating with saidmagnet, a windingon said magnet adapted to carry the alternating currentproduced by the vibrations of said armature, the continuous magneticfinX and the alternating flux, induced during the vibrations of thearmatura-having both the same path, said winding filling the spacebetween the shanks of the U, said field magnet being suitablydimensioned to receive a sufficient amount of whirling to render thelosses of energy in the windings equal to the magnetic energy losses,the thickness of said armature being suitably chosen to retain thearmature belowthe magnetic saturation point for a given flux in theAfieldrnagnet.

7. A magnetic telephone receiver having a U-shaped laminated continuousfield mag'- net, a diaphragm carrying in its central portion a laminatedarmature,a winding on the Shanks of the field I nagnet vand filling thespace `between the shanks and adapted to carry the alternating currentproduced by the vibrations of said armature, the continnous and thealternating' magnetic fiuxes having both the same path, the contour ofsaid field magnet constituting substantially a cube. the thickness ot'each shank being equalto one-quarter length of the enbe edge, thearmature thickness being equa-l to onefifth of the shank thickness, torender the losses of energy in the windings equal to the magnetic energylosses. p

S. An electromagnetic vibrator comprising a laminated U-shaped fieldmagnet suitably constructed to carry a continuons magnetic finx, and avibratoryarmature cooperating therewith, said field magnet also adaptedto carry an alternating flux following the same path as the continuonsflux, a winding on said magnet adapted to carry alternating current incorrelation with said alternating flux, said winding filling the spacebetween the shanks of the U. said field magnet being` suitably7dimensioned-to receive a sufficient amount-of winding to render thelosses of energy in the windings equal to themagnetic energy losses.

9. An `electromagnetic vibrator comprising a laminated vU-shaped fieldmagnet suitably constrncted to carry a continuous magnetic flux, and avibratory armature cooperating therewith, said field magnet also'adapted to carry an alternating flux following the same path as thecontinuous flux, a winding on said magnet adapted -to carry alternatingcurrent in correlation with said alternating kfinx, said winding fillingthe space between the Shanks of the U, said field magnet being suitablydimensioned to receive a snfiicient amount of winding to render thelosses of energyyin the windings equal to the magnetic energy losses,the thickness ofsaid armature being suitably chosen to retain thearmature below the magnetic saturation point for a given finX in thefield magnet.

1Y0. An electromagnetic vibrator comprising a laminated U-shapedcontinuons field magnet and a laminated vibrating armature cooperatingtherewith, a winding on said magnet adapted t carry alternating current,the continuous magnetic flux andthe alternating flux produced by thelalternating current in said winding, having both the same path,4 saidwinding filling the space between4 the shanks of the U, said fieldmagnet being suitably dimensioned ,to receive" a sufficientiamount ofwinding to render the losses of energy in the windings'equal to themagnetic energy losses.

llO

11. An electromagnetic vibrator comprismagnet adapted to carryalternating current, the Continuous magnetic .flux and thealternating/'flux produced by the alternatin'gfcurrent in said Winding',having both 'the same path, said Winding filling the space between theShanks of the U, said field magl net being suitably diinensioned toreceive a sufficient amount of winding to render the losses of energy inthe windings equal to the magnetic energy losses, the thickness of saidO armature being suitably chosen to retain the armature below themagnetic saturation `point for a given flux in said fieldmagnet.

In testimony whereof' I aflix my signature.

HEINRICH HECHT,

